SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98be915976a9f0d8a82be6d31c96be3d26aa1032c09fb146d06d740f3a96ef99' 
  AND token = '2RVbpaZDLsn/BvZWlSzUopqnwoQfZKGKvOWPJP5mRqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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