SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4db50cb0c4850350973a790b3478aba2c6f0276ee794610f2c4543356dbea0cd' 
  AND token = 'dOtPhsxjsSranTW1vdd3pl+7gfauYLvR5JqhypGSWoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}