SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e14694dba242c6c37df4787bcb2399391b3e7c9af65614f617a41d8ae2b6998' 
  AND token = 'w0//oJWdcHGp4BVUxdB8TqD0NQj9+MQQmTpfhCuTMhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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