SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2b7ecfc8b2c0899c2b5e2f67cc0f302048ebdddb320e9e9701a079e00706d96' 
  AND token = 'fRzxD/FFsuqpH05H1LHECzVYB4h1/GMPG8s2kCuhIVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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