SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eba5c03067bab6c2d0de0a3ad7d8afc1ba2954f4457785c27f2470cd49293bd' 
  AND token = '6nPXP5u+poAgwAoe0L7BS+oydqM0xxIWQ4aEKMZ3x6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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