SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9a1b928f723807da746c2757e230fb86f634f41d4db37fb57f7b913c8ce341' 
  AND token = 'FKdnI6aPDdyLArRN/SqZGon34Gu0YVRl1dLITRGo7hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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