SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c5e8432e9cea83eea81ec840b7adfaf3db570d4a45fd1937d2dbd64916c98dc' 
  AND token = '2i6LgbBhjsDN/LVnGMpIlXJIbBzcR+xrco+i3TqR/I8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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