SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15ff3e2620d2150312f56546a524aa8faea6193f7087d95e5ab84ca4ddbb6ab1' 
  AND token = '6ZpjBWgBN/9MVQdRIwhtJdm/U41LpJQDi3jhTMTC0cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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