SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44e6b84e86ee766fefbe575b42dd72befa194695789d2697b75a33fe58609629' 
  AND token = 'Zoj35EYxLqGd+ZHD+tEyoF0VhSZsZk/kLkdijq9Bi4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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