SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7268baebe201b1cf83e7542659f2e47c8f95ed659777c9d0f5cfafdb7e3e9e91' 
  AND token = 'L+r1rjB7i+635GN8HOeS+/iYAcZybFOOdrI4M8NZqQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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