SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bf0e56297bab8757076a2d1f34b5ef4acda63df6df8d35476994a3441eef377' 
  AND token = 'o3FJVIMOqLQWv6JG31uqbXX63xdcONk/AnQrbLsEcgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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