SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9567da7a01f843d0f3484066f34be59f979fac6f2dab7fa15298cdae7eac4263' 
  AND token = '7aI/aB6L29ju1pq5odLJ3qlxoaZkVa7h+BcDD70bnpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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