SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45d840ff8c0a5131b31c20c787fc241c6c31bad702e2aa0668368514c250054' 
  AND token = 'narGlGTB8jb6HbsQnJ4pL4sw9YkoqU4Y3Ltnxhlv9Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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