SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896936e92cff5670ce104cf695abf2dff5a3a906c988b63fe1b53b35d21b666b' 
  AND token = 'ZfIHQxgEY4uPeZkwPqUjIxm5kqvhrifVJIz+CYStQpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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