SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68892fe1272a7ffece6219b8381ce8c3e2f92aa6fd07efd856bbf738e6a593b6' 
  AND token = 'cQ79Uozg59/CDpSVYd0TECBOgc7IOXLmDVToUlmYcvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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