SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5101a5c60957ce70dea9f5b6fcd87d7068fe67cce22dd0c254718949e1548923' 
  AND token = 'crSoNHIQ28IZ+kOH4Dbv59k7SejV0nWfDGQrcWdYRZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}