SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aca98eaa15743ec9adb21c6cfe688acce9545c103e8cbeea6cec892324a863f3' 
  AND token = 'yfRO7AbUdSW3c2vIMihJLcqJmRZA8WD+OQ5EMYC4Wmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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