SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5762529d265d6b54bf4803a1eaa795fcec751a09ea60aa81ff59d762181275ac' 
  AND token = 'turpbIK1aoYcBr0o6yGiDdkqToROq3hUkXUaqjxrhho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}