SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0bfb970bc5faf11fdd3b8728700c5f50a0aba4d31b1c228df3722cab6776802' 
  AND token = 'ds27kAtsOwcr4bqzlt8besRx8wRSZHu4s+6STREqZLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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