SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a67fef0ac3bae6a40a39b2ea4ba7891ac69f62a3ce2d297d8dd7e0bca57215d' 
  AND token = 'ZV/wJcJUiveEqeFdYECyxCTSTqRY+R02VCNO+X2henk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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