SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3338caa19a47e3931579b0452e1c8b47f268c9843d4c3474e1bcc8021ad55d6' 
  AND token = 'NVLBiGQTvZAvoiirlhJleqmFoITUP21I8Q+hR6ZqvL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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