SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fced3f5f6d9f009ee3f2fceec4306b458a80885c19f4c938fdfdd7325ff9b2ef' 
  AND token = 'b/AlUFUKblkePdrUSLGWURpgc2iH5PTXeS0xQOnTayc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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