SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e82504470302843399cbab0f94dcf2d8789463307b29a5f42ab7c1d0ede76720' 
  AND token = 'CDUT+pGFwRrO6aSCei72wjk9leBlTT7RlyiNtiWRKfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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