SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b75d5937cd8db9351300a7ac226b0c2bc63287f9304e781f04a92241657654' 
  AND token = 'dFlmP4ccu1/YABQeCk4+nvLjEE80zGq8JTqK8LSDlsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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