SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ce844e390a861976d6fe955bee538018abcf3e09aeba369807c2bbaf7ada2e1' 
  AND token = 'jzz1MQDZsoJ8JqsFzxVHkEukfK9mRUXuE4tI9J+aGE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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