SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f689a3c6576291efe2810d3a170d6a6a47eed938573b5b52e4a673ceab82794' 
  AND token = 'Kbg1+qiQz5KjLNF3X3DK8LGp9pA3dOorc3jlpZ/wtGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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