SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c3a85491aeae19c5336828ad2917e9ad2004db7afdf61924838d965f3a986f7' 
  AND token = 'eeCCLWROUjZGDY8aVCdqufopRMx22pnWr7jetJSwP5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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