SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '942c2a92b4e619333d3369f7581db69a057be33ee25669fbb6d4be9d861a1bba' 
  AND token = 'tmZa7UlZIuuWt6Kn9+AQtG6ocYwD0GkdS3NCUCmwvGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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