SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a0e484647850174a574b0b99326e447ace1c1f099137689d810a7307583dc4' 
  AND token = 'kcDC+KyjiFv5jTluZijiprgzQjtdavlmsGmEbCDtTlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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