SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c5317bdfd38fc47aea6f470073717afd014818501d1015937cbd7a23a11b25' 
  AND token = 'B7ajq0It95VOnrvzPO3K4hrl3cXfv+CccRQQYujMCsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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