SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fd38caa7a8bd1187d6471ba53d7b27503998d274a2d860f68815db51e3a3585' 
  AND token = 'h42JRAMUvSkJeGp9qwS/h/VPFwcfBKd/miJUb0sEyl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}