SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9609a4f95bceaf2623e888a135a65203c43425fbbaeb4121547384c838a1759e' 
  AND token = 'VQ94Dv9zEtVHgtdjNo5pAYAj4lKY7U3QVZJR6y3WSgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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