SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a14fdc9d4a8d3b68f8c77c3ae0d749f31ef75d727562a517141f0a26e08cb484' 
  AND token = 'P0ip8HA3jvwsjSLYzGDzi6hz4Ls9KiVJaQONSthIQCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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