SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61841891117d8980659991804ebd12e2eadaaced17ababe786cb1879a93c3466' 
  AND token = '8hsQ8LcRCJ9SrdQMuByV5KFQ3JMUYgljNhAhPgMCf30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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