SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b0335be2e2b6f0ac09cba9d9ab0345e03ba141f51f33261169e405b315e85d' 
  AND token = 'Oxtwfcm4iHc1p9lrhaYMWsqDAmXSQpKrLjX+0QkZZlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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