SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd61b373415edd6309acdfca258fa80f3647acad40e581230a306ee36d42f68a0' 
  AND token = 'O8KwWsw2tXeSr8TuNdeJYWNjyphiAOQ1LqByi84uEJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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