SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a852b74ebb8b0f2329b9d6c3c1f74bc1f103ea9d1899614f643375acbd6616' 
  AND token = 'oUnb/+DBTvr0735xneTQCJ8oU/ASnZMMe7gbhzqln2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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