SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ebc24dd5798edb1be6f2450b4b7284429fbd3e18886dfcd2a642e46683e053' 
  AND token = '2EfyI96hTfZL01dqV9so5cwH9CvyRJNufAFy8yZtKUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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