SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd3ef604ee0f87c0c0b8ce5947ac18786b6c79afa0f38a26e268044ee49feb94' 
  AND token = '2Fkg3J5WHClfqvUup3gAf4ZSJlYhmLTUKTqI54+/Z2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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