SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ed421382c87797ebd9d4cc10ed30efa1d7432f414302fdd7caa0514a4302da4' 
  AND token = 'kq7juW9Qe6HZaPTlyBlz1gWF4Xy8tOURYoEusM1FDtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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