SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad0c4f1dee1bbe4532bf8c6575f3e9a01dd8984edb4b92c5c86e70b1071a45a' 
  AND token = '7FJJYZmU/tJYIEi+nDMZ/ou7dHquAgEN6cVMiadroRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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