SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142e6f69bcc612d87805c4d134427a08725e19f8dfd8a9fb0eed4e5d8a176cc5' 
  AND token = 'jfrThy2XnBAFGzCtblWOxNnExyQ/4xpuHg3YtuVXGT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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