SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '377ac625dc646224c787e83f6b0fd241ee3b88d8aedd8ca9f39b8859116e7ffa' 
  AND token = 'w7WDWaXMBipfXc4rEdl8VmvNhe34ht3/jGyPdaUUms8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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