SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b6c92218593cf18564a7f0088704d0eaaf174289936769fff1bb4c1bae11e96' 
  AND token = 'o+14SWom2TruKVNOS1Kw2zeMSZT59FUity6+54Rhh2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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