SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6763fbef2be0dda8cbc20643a4d7665be189df10c532a243034e539b62f3ffd3' 
  AND token = 'Fbf+ObAVb5WXCpP48aVE8s0VWA3lrJmIvS3xkghcR2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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