SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3451fb02b5f6e4a801ed1788a13a2b40adf4dd70025e07538993431cf16511fa' 
  AND token = '7RKMEGJa9OCg7qxKkbsVZlmhqv/PICqQCx9nCFPSLEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}