SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d9734f777f57681f2b216f0c83ac40e4ad8821f5d335b755154afb3cade3bf' 
  AND token = 'vMx1QBgoya5z7qIM/YqiGVdqIe8lDZlxZGz1UoZBxNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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