SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b7f4ff461e4571b69c58398b99cbc61e3e56a52eadf08141a17f7db6c1f1ae' 
  AND token = 'RHZALA303K1zMoPnZ+jHmeTDAk7yxwV+qwDRWiAd0uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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