SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e312fd745bd2ce2008d8404c148e70673872c002ee95c08f2c3fd584ed371ecb' 
  AND token = 'Czsfxqhw7iGNtVG3Gf0JTgKX4xLxvNlL7in+/Eh7Ldo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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