SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfc77472ac4bb80896d1ce093a437a91005655d509b25774d69bd395f1e32a69' 
  AND token = 'PSVzIVzLcNP/f2cSrBPE/UbSifYI5aVhOIaQyoferrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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