SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '706a8d00b74f84321533a2647310c5a86f05c147c3d14d1203c7d033cd9860e7' 
  AND token = 'K1cGpQ5BlDEwx4MI1XYv4IGt/VHsDkqVwNOCeydgDM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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