SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0b2a1bcafa0022b1a4415de1df4e6acd184ce35aa426af0fd8f56e308f76f4a' 
  AND token = '1fMl5iuSFfdlrWUbLcbjkll1aEdeRNpO6B5zJblCXD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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