SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff6352403154d34bb29b6675e1317ac030b833a397918ddda575eb0d13544e49' 
  AND token = 'SNQBJR357BhmplpF6SFjxAAJhHaj4h84s/AV+yCw8hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}