SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d2aa1fe553d45adaaebd50ef44a1cf739994a561296ac413dff4e9e61dad2a' 
  AND token = 'LUlHVe5dcxbgc7q5i7GyGGZpsudCauw0XeOvlScyuBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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