SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b3c2f882d32b2dc36ceda11ff1c88c5c1eb5966888c28abd80dc082e7610a76' 
  AND token = 'EkOrz39xCmVJ6eioy+dkU+Pu1YRObZotsXW6nXykMVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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