SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e088b8079638ff3af605a5e5c6623e2dbcb190b3d3d3654c377f2bcaa1b850ad' 
  AND token = '9QUTb8SvBgWKc45Mnnp6EyLE22kjpk5Zngfor7QZ3wE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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