SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78585a6232148dee2a456fbfdab2057973f735fd205b1bc503c4ee567136d7c9' 
  AND token = '81AsZowlkGW78Wb5BsKvzJHiTGPKyThv838Z/4uJYJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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