SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d121cfb3e169b035f23787b2e138ee59df62a2f195666e9a6989514c195ce8b' 
  AND token = 'giYwntNqJ+/1TpVaO4/nmm2twim/CgJNca25AnNwq2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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