SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40b324d06036d48b19e53a24472fddd90bb1ea114edf87c685fc3406bc4e5eae' 
  AND token = 'LHxhwX+XbJsXbb8j1NOnFPSCTlx9rbUMhrW+TJgalwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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