SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8118375b04ffb04345a9fe7f821ce39b77a25a7051b769cdc49b20f447c86f8f' 
  AND token = 'k2WYEa6APRwG5VPWw+mYjwmuYOKbhflgQqmwql2kPak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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