SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10e3ff16311868fffc0696fc724fea7c091f9f08798af930181af208191a399a' 
  AND token = 'Ei+rYnqOSvos5/HzYuZPSjELeID56aa0ZW1Nz+R8DtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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