SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c49608170a5e406a132567fd593018cae33f150cb6a74698ce689a592552c415' 
  AND token = '9GkuBdBZya2PLXBgnvJdBLam6CyuOEceDu0NEXbIKvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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