SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b9f1169c0785be6e0610dbf1132759b376fabac4fbe3e0d0c6f0499eb63ad7f' 
  AND token = 'TVegVOD54v2dzP/U99Rgq3N5NjJJnvyYnSijrYwhuL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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