SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a7778689b88209a7a06e0e684f222256160d4a7bcb0fcaa48bf50f0d7230e83' 
  AND token = 'n/xiqJF4+Y4dnaKi1DvKghST3BFsrez+lLwSdD+Ptqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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