SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd98f37ac627ae9939ec6e846cf811bcd558b201622444d341992308815533006' 
  AND token = 'BzVw6c9+oJc0ExZ4ZzTmAzDSQIpR1UveK/421IoDbBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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