SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1edf022b51e84650164875aad37ffde2dc61b20fa03c7fc51aa550ac2ecf68a7' 
  AND token = 'B1u4Cz0ORJZSbCpg9Qsro6gmdHfHVR2jlAyWJ68f54c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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